1. Technical Field
The present invention relates to a method for forming a conductive post, a method for manufacturing a multilayered wiring substrate, and a method for manufacturing an electronic apparatus.
2. Related Art
A technique to form a constant material pattern by discharging a liquid containing a desired material so as to be landed on a predetermined position by employing a droplet discharge method (ink-jetting) is now being vigorously developed. Such a patterning technique enables a fine liquid to be applied in a desired position corresponding to resolution of an inkjet head to be used, thereby forming a fine pattern. For example, a fine wiring pattern for a circuit substrate can be formed by applying a wiring material or a solution of the wiring material.
However, such a method is easily affected by a property of a surface to which a liquid is applied. For example, if a portion on which a droplet of the liquid is landed is easy to be wet (lyophilic) with respect to the liquid, the applied droplet may spread out to extend larger than a desired shape. On the contrary, if the portion on which the droplet is landed is hard to be wet (lyophobic) with respect to the liquid, the liquid may agglutinate on the surface to be landed and form a liquid accumulation (bulge), also resulting in not forming a desired shape.
By the way, with response to requirements of down-sized and multi-functioned electronic devices in the market, electronic circuits tend to be highly dense and/or highly integrated. One of the techniques to provide highly integrated electronic circuits is a multilayered wiring structure for circuits. In a circuit having such a structure, an electronic circuit is not only planarly formed, but also vertically formed by layering circuit substrates, successfully providing a highly integrated circuit in a small mounting area. In a case of employing such a multilayered wiring structure, as a method for coupling wiring patterns on layers to each other, a conductive post is formed on an insulation film between the layers so as to couple the layers through the conductive post. When this method is employed, the conductive post to be formed is also required to be minute for a need of a highly dense and/or highly integrated circuit.
As a technique to form the conductive post, JP-A-2003-282561 and JP-A-2006-140437 disclose forming methods employing a droplet discharge method. Specifically, when an interlayer insulation film is formed by applying a liquid containing an insulation film forming material (insulating ink) with the droplet discharge method, a region not having the insulation film is formed by not applying the insulating ink on a conductive post forming region, so that the region not having the insulation film can serve as a conductive post.
However, in the method described above, when the conductive post is formed in a portion having well wettability such as metal wiring or the like, for example, the insulating ink having been applied is easy to spread out other than a desired region, thereby causing difficulty in controlling the conductive post to be in a desired size.